Assume that a country that once had a lucrative oil-producing industry experiences a rapid fall in market prices that has caused numerous oil exploration and drilling companies to stop production. The result is many oil exploration and drilling industry workers out of work and tremendous amounts of oil exploration equipment left sitting in the equivalent of "used car lots" to be sold.

• Which of the 12 basic economic principles outlined(#1: Choices Are Necessary Because Resources Are Scarce, #2: The True Cost of Something Is Its Opportunity Cost, #3: "How Much" Is a Decision at the Margin, #4: People Respond to Incentives, Exploiting Opportunities to Make Themselves Better Off,#5: There Are Gains from Trade, #6: Markets Move Toward Equilibrium, #7: Resources Should Be Used Efficiently to Achieve Society's Goals, #8: Markets Usually Lead to Efficiency, But When They Don't, Government Intervention Can Improve Society's Welfare, #9: One Person's Spending Is Another Person's Income, #10: Overall Spending Sometimes Gets Out of Line with the Economy's Productive Capacity; When It Does, Government Policy Can Change Spending) in the course textbook best describes this situation?